Fuel pump



g- 1, 1967 D. R. COMPTON ETAL 3,333,547

FUEL PUMP 2 Sheets-Sheet 1 Filed July 30, i965 ,INVENTOR DONALD R. COMPTON BY JOHN B. FITZGERALD ATTORNEY g- 1957 D. R. COMPTON ETAL 3,333,547

FUEL PUMP Filed July 30, 1965 2 Sheets-Sheet 2 55 INVENTOR F I G. 6 DONALD RCOMPTON BY JOHN B.FITZGERAL.D

ATTORNEY United States Patent Office 3,333,547 Patented Aug. 1, 1967 3,333,547 FUEL PUMP Donald R. Compton, Belleville, Ill., and John B. Fitzgerald, St. Louis, Mo., assignors to ACE Industries, In-

corporated, New York, N.Y., a corporation of New Jersey Filed July 30, 1965, Ser. No. 475,933 6 Claims. (Cl. 103-150) ABSTRACT OF THE DISCLOSURE The invention relates more particularly to a noise dampener or suppressor adapted to use in a diaphragm type pump. Physically the diaphragm or pump rod, reciprocably guided through the pump dasing guide passage, is provided with a resilient cushioning member. The latter member is so positioned to absorb the impact of the pump driving arm and also to absorb side thrust of the pump rod as the latter tends to strike the guide passage walls. The cushioning member is further reinforced by the provision of an internal core with a support collar depending therefrom to brace the core against the shock of both the pump arm and the pump rod striking the guide passage walls.

This invention relates to fuel pumps. It relates in particular to pumps used in automotive devices for pumping fuel to an engine, providing vacuum source, or both.

Automotive vehicles often utilize a mechanical fuel pump to provide a flow of fuel from the fuel tank to the engine carburetor. Such mechanical pumps consist of a reciprocable member mounted in the pump housing, and having one end in engagement with an engine drive cam. The other end of the reciprocable member embodies a lost motion connection to the fuel pump rod for actuating a flexible diaphgram.

The pump diaphragm under normal operating conditions, provides a movable wall defining a pumping chamber, the latter being connected to the fuel tank by means of a valved inlet passage, and thence to the carburetor through an outlet check valve. Operationally, the diaphragm is displaced through extreme positions by the reciprocable member, thereby directing fuel into the pump chamber. Simultaneously, a spring means cooperates with the diaphragm such that when the reciprocable member changes direction, the lost motion connection to the diaphragm rod disconnects the latter from the diaphragm. The compressed spring thus biases or displaces the diaphragm in a pumping stroke to force fuel from the pumping chamber and into the outlet passage of the pump.

Pumps of the type described are operated by the reciprocable member during the intake stroke only and are operated on the pumping or return stroke by the biasing spring. The lost motion connection between reciprocable member and pump rod permits said members to readily disengage. This occurs when there is a pressure build-up in the fuel outlet line and the spring fails to bias the diaphragm in the pumping direction. Thus, the reciprocable member is free to operate in an axial direction fuel as it is used by the engine. However, as the recip rocable member operates, the pump rod moves into the path of the reciprocable member and is struck on each cycle by said member.

This periodic contact of the reciprocable member with the pump rod provides a distinct click or slap which is clearly audible during idle conditions in the presence of low background noise. Further, when the engine runs at idle conditions, the pump rod is repetitiously struck by the reciprocating member when the diaphragm is displaced to its extreme position near or after the intake stroke.

It has been found beneficial to provide the pump rod connection with a degree of resilience thereby overcoming much ofthe above noted noise problems. This is done in one way by means of a resilient pad like arrangement as shown for examplein U.S. Patent 3,186,349 (D. R. Compton et al.). Here the resilient pad is so positioned to function as a cushion and eliminates most of the usual noises.

Another source of undesirable engine noise originates as .a result of the pump rod acting in its normal axial movement. Ideally, the rod will reciprocate under all conditions along a path traced through the pump casing and normal to the diaphrgam. However, this movement is infrequently an actuality. For one thing, the pump diaphragm spring does not always exhibit a line of force which extends along the spring longitudinal axis. Rather, the line is directed along a vector which is canted from the axis. Thus, there will be a tendency for the biasing spring to urge the pump rod in a direction non-coaxial With the pump rod guide passage.

Also, the reciprocable member being pivotally mounted at its engaging end, traces a generally arcuate path of travel centered at the pivot point. Since the rod end and the reciprocablemember are ordinarily held in close, non-sliding contact duringxa pump intake stroke, the pump rodwill be urged from a position abnormal to the diaphragm. When the latter occurs, as the reciprocable member changes direction and moves downwardly toward the diaphragm for -a pumping stroke, the rod end will be suddenly released. If the rod end has been strained radially out of alignment from a vertical position, upon release the rod will tend to whip in an arcuate direction and relieve the strain. The result of this sudden release of the rod strain will result ina sharp striking of the rod end against the walls of the guide passage.

Still another cau'sefor the undesirable distortion of the pump rod from a verticle path of travel results from the flexing of the diaphragm. The latter, in traveling between extreme positions will tend to flex and be generally unbalanced, which imbalance is transferred to the pump rod.

Continuous operation of the pump when the rod is permitted .to oscillateradially as above noted can produce a highly annoying repetitious click of the metallic pump rod against the metallic guide passage wall. The noise is not only undesirable, but causes excessive wear at one or more points in the passage wall which could lead to an eventual failure.

It is therefore one object of the invention to provide means for eliminating in a fuel pump the above noted undesirable noises.

It is another object of the invention to provide a noise dampening means in an automotive pump which tends to reduce the noise produced by contact made during operation between the pump driving member and the pump driven members.

It is further an object of the invention to provide noise suppressor means to eliminate undesirable noise as well as wear, in cooperating pu-mp parts.

A still further object is to provide a resilient guide member carried on an oscillating pump rod to avoid sharp impact contact between the rod and the pump casing.

In the accompanying illustrations, FIGURE 1 is a schematic view of a vehicle having an engine utilizing a pump embodying the present invention.

FIGURE 2 is a sectional view in elevation of a fuel pump mounted to the crankcase wall of the engine shown in FIGURE 1 and incorporating the novel feature of the invention. 7

FIGURE 3 is a segmentary view taken along line 4-4 in FIGURE 2.

FIGURE 4 is a view similar to FIGURE 3 showing the guide assembly biased into contact 'with the opening formed in the guide chamber.

FIGURE 5 is an alternate embodiment of the novel guide assembly shown in FIGURE 2.

FIGURE 6 is a cross sectional view taken along line 6-6 in FIGURE 5.

FIGURE 7 is a cross sectional view taken along line 7.-7 in FIGURE 5.

FIGURE 8 is another alternative embodiment of the novel guide.

FIGURE 9 is a further alternative embodiment of the novel guide assembly.

In brief, the invention resides in the use of a resilient guide assembly disposed intermediate the reciprocating drive means of an automotive pump and the driven pump rod such that undesirable noise produced as a result of contact between the two and with the pump casing is dampened. The resilient guide assembly is supportably maintained at the pump rod end by a metallic collar which is carried on the rod end, and, having an outer diameter which is less than the diameter of the resilient member. Thus, during pump operation as the pump rod and the guide unit are urged along a pump rod guide passage, the walls of the latter will be contacted only by the resilient member rather than by metallic parts of the push rod which contact would ordinarily result in an undesirable noise.

FIGURE 1 schematically represents a vehicle 10 having an engine 12 for providing automotive power to the vehicle. Engine 12 is of any well known design having an air filter 14 mounted on a carburetor 16 with its outlet connected to the intake manifold 18. Fuel is delivered to the inletof carburetor 16 from a fuel tank 20 through a fuel line 22 by means of fuel pump 24 whose discharge line 26 is connected to the fuel inlet of carburetor 16.

I The invention is shown specifically in FIGURE 2 embodied within the pump 24 mounted to crankcase 28 of engine 12. Mounting of the pump to the crankcase may be in a conventional manner such as :by threaded studs which extend from the wall of crankcase 28 through flange 30. The pump consists basically of a housing 32 which defines a cavity from which depends a valve casing 34, the edge of the latter being connected to the lower side of the casing thereby defining an enclosure.

As shownin FIGURE 2, housing 32 embodies a pcripheral lip 33 forming an opening to the housing cavity.

a The valve casing 34 includes a rim 35' complementing lip 33 and spun over the latter to form a circumferential tight seal at the pump exterior.

As is normal in such pump construction, casing 34 is provided with a pair of downwardly depending wells 29 and 31 which, although not presently shown, enclose the respective inlet and discharge check valves for regulating the flow of fuel passing through fuel chamber 27.

A pump diaphragm 36 is compressiblyheld at its periphery intermediate the beveled edge of rim 35 and the mating edge of lip 33. The diaphragm is maintained sufiiciently tight by the wedging action of beveled rim 35 and valve casing 34 such that the inwardly deforming of rim 35 across the top edge of lip 33 will furnish a fixed, permanent joint.

Diaphragm 36 when so positioned in the enclosure, define oppositely positioned fuel chamber 27 and pumping chamber 37.

Diaphragm 36 is rigidized by a pair of oppositely disposed plates 38 and 39 which extend across the central portion of the circular diaphragm. Lower plate 39 in cludes a central opening and a downwardly turned rim 40, the latter supports diaphragm 36 along a smooth curved surface. Upper plate 38 is similar to plate 39, having a central opening and an upturned rim 23 which similarly supports diaphragm 36 along a smooth curved surface. Plate 38 includes a centrally positioned, circular raised bead 25 forming a retainer wall for spring 41.

A first Washer-42 is held adjacent lower plate 39; a second washer 43 similarly abuts the upper face of plate 38. Diaphragm assembly is maintained as a unit by a pump rod 44 having a lower end which registers in the aligned central openings of plates 38 and 39, and washers 42 and 43. An annular collar 46 abuts washer 43 at the protruding end of rod 44, is then upset or riveted to form a One end of arm 49 is bifurcated, forming a slotted opening adapted to receive the shank of pump rod 44 and bear against the under side of guide assembly 53. Arm 49 further includes a first contact end extending through opening 51 into the crankcase 28, to engage a rotating eccentric cam 54.

Housing 32 is provided at the upper side with a well 56 in which a cup-like spring retainer 45 is held to compressibly position spring 58 against the upper edge of arm 49 thereby maintaining a continuous contact between the surface of eccentric cam 54 and the arm 49. Retainer 45 includes a peripheral lip 71 which engages an intruding shoulder 72 to be held in place.

Referring to FIGURES 2 and 8, guide assembly 53 is carried at the upper end of pump rod 44 and positioned thereon by an upset head or cap 69. Guide assembly 53 includes a rigid support sleeve 61, comprising a circular base 62'having an outside diameter less than the diameter of chamber 48. A longitudinal bore in base 62 is defined by an upstanding flange 64, said bore receiving the upper end of pump rod 44, preferably although not necessarily in a tight fit.

Again referring to FIGURES 2 and 8, a resilient memon the shank of pump rod 44. Said pump rod 44 end is 7 thereby retained in cavity 48 formed in the casing. Seal assembly 67 is urged into seating position casing 32 by spring 41 which is compressibly retained against upper plate 38.

In accordance with the invention, as arm 49 is reciprocably actuated about point 52 by the rotating cam 54, arm 49 will engage and urge the pump rod 44 upwardly during the pump intake cycle stroke. As the arm 49 responding to cam movement, changes direction, the diaphragm 36 will be urged into the pump stroke by the force of spring 41.

As previously mentioned, during the above sequence of steps comprising the intake and pump cycle, the actuating end of arm 49 will be in abutting engagement with the upper surface of resilent member 66 and particularly in opening 73 for-med in the lower face of said member. As shown in FIGURE 2, the end of arm 49 is curved slightly to be normally received within or adjacent opening 73 in resilient member 66. When arm 49 engages the resilient member 66, exerting a force thereon, said member will be compressed and slightly deformed thereby permitting arm 49 to engage the edge of flange 64. Thus for an intake stroke, the upward force transmitted to pump rod 44 during the intake stroke will be cushioned by resilient member 66 although the latter is rigidly supported by the support sleeve 61. Simultaneously, during the intake stroke the periphery of resilient member 66 will be deformed slightly in a radial direction, in response to the arcuate path of the arm end thereby engaging the Walls of chamber 48.

For each pumping cycle then, rod 44 and diaphragm assembly 36 are actuated through the pump housing, rod 44 will tend to oscillate within chamber 48 due to the canting action of spring 41, the flexibility of the diaphragm assembly, and also the lateral displacing force exerted by the pivoted arm 49.

During the downward "stroke of arm 49, since pump rod 44 is released of the restraining hold of arm 49, the rod will tend to assume its normal unstrained position, which action resulted in a sharp impact between the wall and assembly 53. In accordance with the invention, any realigning of the upper part of the pump rod 44 which would bring the latter into forceful contact with walls of chamber 48 will be cushioned due to the resilient contact of the peripheral edge of resilient member 66 with the chamber Walls.

It is clear that the present invention has overcome a persistent and annoying obstacle which has heretofore precluded development of a quietly running fuel pump. This problem of lateral oscillation of the pump rod due to the pivoted motion of arm 49 is particularly accentuated in the instance of pumps with increasingly lengthened stroke.

Due to the configuration of resilient member 66, the lower larger diameter of said member will tend to resiliently engage the walls of chamber 48 and provide a desired noise deadening effect.

FIGURES 5 to 7 illustrate an alternate embodiment of the novel guide assembly 76 which includes a resilient member 77 having a body portion with a central opening 78. The peripheral edge of said body 77 includes a plurality of substantially equispaced protruding members 79. A support member 81 includes a base 82 having a plurality of downwardly protruding fingers 84 corresponding to members 79. The resilient member 77 is held within the confines of the support member 81 by the fingers 84, the latter being spaced inwardly of the periphery of said resilient member so as to avoid contact with the side walls of the chamber 48 as push rod 44 is reciprocated.

Resilient member 77 may consist of a rubber, plastic or similar material, and be molded in place to form a unitary assembly with support member 81. When such a construction is followed, the entire guide assembly 76 may be slidably carried on the end of pump rod 44 to permit rotation of the guide assembly and thereby distribute the wear of the peripheral surfaces which contact the walls of chamber 48.

In a manner similar to that described with respect to the embodiment shown in FIGURE 2, the periphery of the resilient member 77 will be brought into sharp engagement with the walls of chamber 48 during operation of the pump. Thus, the degree of indentation of fingers 84 is sufiicient to permit contact only between the resilient member and the adjacent walls. Further the contact face of resilient member 77 is positioned in advance of the forward face of support member 82, thus permitting a cushioning of arm 49 against the surface of resilient member 77 prior to the arm bearing against the'face of member 82. It is understood that the herein described guide assemblyunits may be formed individually but are alternately molded in a single operation.

- FIGURE 9 illustrates an alternate embodiment of the invention including a resilient member having a peripheral upturned edge 91 defining a circular cavity. A support member 92 is received in the central opening of the resilient member and said support member including a center opening adapted to be received on the pump plunger shaft.

It is further understood by those skilled in the art that the foregoing description is a preferred embodiment of the disclosed device and that various changes and modifications may be made in the invention without departing from the spirit and scope thereof.

We claim:

1. In a diaphragm type fuel pump having,

(1) a casing forming a cavity,

(2) a guide passage in said cavity,

(3) a housing including valved inlet and outlet ports, said housing being sealably connected to said casing to form an enclosure,

(4) a spring biased diaphragm disposed transversely of said enclosure forming opposed pumping chambers, and

(5) an arm pivotahly carried on said casing, having one arm end extending into said guide passage, and the other end thereof being adapted to be reciprocably driven for actuating said fuel pump,

(6) an elongated pump rod attached to said diaphragm, extending into said guide passage and engaging said arm one end to be axially reciprocated by said arm,

I thereby displacing said spring biased diaphragm,

(7) a guide assembly carried on said pump rod and positioned to receive said one end of said arm and cushion the rod from shock during operation thereof, said guide assembly including;

(a) a rigid member including a cylindrical core fixed to said rod, and a collar depending from said core,

(b) a resilient member surrounding said core and supported by said collar, said resilient member extending radially outward toward the walls of said guide passage to overlap the collar peripheral edge and having a face positioned to receive said arm one end,

(c) whereby, during a portion of the pumping stroke, said one end of said arm is in abutment with said face of said resilient member to actuate said diaphragm against the bias of said spring and to displace said rod from a position normal to said diaphragm, and during the return pumping stroke, said arm will reverse direction thereby releasing said pump rod and permitting the latter to adjust laterally to a position normal to said diaphragm whereby said resilient member will laterally cushion the impact of said pump rod as the latter strikes the walls of said guide passage.

2. In a fuel pump as defined in claim 1, wherein said rigid support collar is disposed at the side of said resilient member opposite to the said face thereof.

3. In a fuel pump as defined in claim 1, wherein said resilient member includes a recess formed in the face thereof adjacent to said support collar the latter being recived into said recess.

4. In a fuel pump as defined in claim 1, wherein said resilient member is loosely retained on said core to permit rotation of said resilient member during reciprocable movement of said pump rod.

7 8 5. In afuel pump as defined in claim 1, wherein said 7 References Cited resilient member includes a peripheral surface formed in V UNITED STATES PATENTS a generally tapered configuration having all P01110115 there- 2 291 074 8/ 1942 Flint 103 150 xi 3 g gs outwardly beyond the perlphery of sald 5 72,426,965 9/1947 coffay 3,096,721 8/1963 White 103-150 6. In a fuel pump as defined in claim 1, wherein said collar includes a plurality of upstanding spaced apart tabs KIN at the collar periphery, to rigidly position said resilient DONLEY STOO Pnmary Exammer' member, said tabs being recessed beneath the surface of ROBERT M. WALKER, WILLIAM L. FREEH, said resilient member. 10 Examiners. 

1. IN A DIAPHRAGM TYPE FUEL PUMP HAVING, (1) A CASING FORMING A CAVITY, (2) A GUIDE PASSAGE IN SAID CAVITY, (3) A HOUSING INCLUDING VALVED INLET AND OUTLET PORTS, SAID HOUSING BEING SEALABLY CONNECTED TO SAID CASING TO FORM AN ENCLOSURE, (4) A SPRING BIASED DIAPHRAGM DISPOSED TRANSVERSELY OF SAID ENCLOSURE FORMING OPPOSED PUMPING CHAMBERS, AND (5) AN ARM PIVOTABLY CARRIED ON SAID CASING, HAVING ONE ARM END EXTENDING INTO SAID GUIDE PASSAGE, AND THE OTHER END THEREOF BEING ADAPTED TO BE RECIPROCABLY DRIVEN FOR ACTUATING SAID FUEL PUMP, (6) AN ELONGATED PUMP ROD ATTACHED TO SAID DIAPHRAGM, EXTENDING INTO SAID GUIDE PASSAGE AND ENGAGING SAID ARM ONE END TO BE AXIALLY RECIPROCATED BY SAID ARM, THEREBY DISPLACING SAID SPRING BIASED DIAPHRAGM, (7) A GUIDE ASSEMBLY CARRIED ON SAID PUMP ROD AND POSITIONED TO RECEIVE SAID ONE END OF SAID ARM AND CUSHION THE ROD FROM SHOCK DURING OPERATION THEREOF, SAID GUIDE ASSEMBLY INCLUDING; (A) A RIGID MEMBER INCLUDING A CYLINDRICAL CORE FIXED TO SAID ROD, AND A COLLAR DEPENDING FROM SAID CORE, (B) A RESILIENT MEMBER SURROUNDING SAID CORE AND SUPPORTED BY SAID COLLAR, SAID RESILIENT MEMBER EXTENDING RADIALLY OUTWARD TOWARD THE WALLS OF SAID GUIDE PASSAGE TO OVERLAP THE COLLAR PERIPHERAL EDGE AND HAVING A FACE POSITIONED TO RECEIVE SAID ARM ONE END, (C) WHEREBY, DURING A PORTION OF THE PUMPING STROKE, SAID ONE END OF SAID ARM IS IN ABUTMENT WITH SAID FACE OF SAID RESILIENT MEMBER TO ARCUATE SAID DIAPHRAGM AGAINST THE BIAS OF SAID SPRING AND TO DISPLACE SAID ROD FROM A POSITION NORMAL TO SAID DIAPHRAGM, AND DURING THE RETURN PUMPING STROKE, SAID ARM WILL REVERSE DIRECTION THEREBY RELEASING SAID PUMP ROD AND PERMITTING THE LATTER TO ADJUST LATERALLY TO A POSITION NORMAL TO SAID DIAPHRAGM WHEREBY SAID RESILIENT MEMBER WILL LATERALLY CUSHION THE IMPACT OF SAID PUMP ROD AS THE LATTER STRIKES THE WALLS OF SAID GUIDE PASSAGE. 